title: Anisotropic breakdown of Fermi liquid quasiparticle excitations in overdoped La₂-xSrxCuO₄.
abstract: High-temperature superconductivity emerges from an un-conventional metallic state. This has stimulated strong efforts to understand exactly how Fermi liquids breakdown and evolve into an un-conventional metal. A fundamental question is how Fermi liquid quasiparticle excitations break down in momentum space. Here we show, using angle-resolved photoemission spectroscopy, that the Fermi liquid quasiparticle excitations of the overdoped superconducting cuprate La1.77Sr0.23CuO4 is highly anisotropic in momentum space. The quasiparticle scattering and residue behave differently along the Fermi surface and hence the Kadowaki-Wood's relation is not obeyed. This kind of Fermi liquid breakdown may apply to a wide range of strongly correlated metal systems where spin fluctuations are present.
authors.affiliation: 1] Institute for Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland [2] Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland [3] Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Chang
authors.forename: M
authors.initials: M
authors.lastname: Månsson
authors.forename: S
authors.initials: S
authors.lastname: Pailhès
authors.forename: T
authors.initials: T
authors.lastname: Claesson
authors.forename: O J
authors.initials: OJ
authors.lastname: Lipscombe
authors.forename: S M
authors.initials: SM
authors.lastname: Hayden
authors.forename: L
authors.initials: L
authors.lastname: Patthey
authors.forename: O
authors.initials: O
authors.lastname: Tjernberg
authors.forename: J
authors.initials: J
authors.lastname: Mesot